Trap and method for trapping flying insects

ABSTRACT

A trap for insects, particularly for wasps, comprises a vapour chamber having at least one insect entrance defined in a wall of the vapour chamber, and a bait or collection chamber couplable to the vapour chamber at a restriction. The restriction is sized to control the movement of insects between these two chambers. In operation, attractant vapour from a bait source accumulates in the vapour chamber and is released through the entrance. Insects attracted by the attractant vapour enter the vapour chamber and are maintained in flight within it, the restriction delaying their entry into the collection chamber. Once tired, insects drop down into the collection chamber where, in a preferred embodiment, they are immersed in a fluid and drowned.

The invention relates to a trap and a method for trapping flyinginsects, in particular for trapping wasps, yellowjackets or the like.

Flying insects, including stinging insects such as wasps, are well knownto be a nuisance in particular environments. For example, in soft fruitorchards wasps can cause considerable damage to fruit, rendering itunsaleable. It is clearly desirable in such environments to be able toreduce insect numbers. A variety of methods have been used to try to dothis, including the use of pesticides and traps. In order to avoidenvironmental damage, particularly near human food crops such as fruit,it is desirable to avoid the use of pesticides. A number of trap designsexist but in tests the present inventor has found conventional designsto be unsatisfactory, primarily because they trap insufficient numbersof insects but also in terms of ease and safety of use.

The invention provides a trap and a method for trapping flying insectsas defined in the appended independent claims. Preferred or advantageousfeatures of the invention are set out in dependent sub-claims.

In its first aspect, the invention thus provides a trap comprising avapour chamber, one or more entrances for insects defined in a wall ofthe vapour chamber, and a collection chamber coupled or couplable to thevapour chamber at a restriction. The collection chamber has no insectentrances, except at the restriction, which controls the movement ofinsects from the vapour chamber to the collection chamber.

In this and other aspects of the invention, the trap advantageouslycomprises a number of important design features to enhance itseffectiveness and ease and safety of use. These design features aredescribed below with particular reference to preferred embodiments ofthe invention for trapping wasps

1. Valour Chamber

-   1.1 The vapour chamber is preferably a distinct chamber from the    collection chamber. The vapour chamber may advantageously be    manufactured from a clear plastics material, such as PET    (polyethylene terephthalate). There are three principal functions of    this chamber:-   1.2 The vapour chamber is advantageously designed to maximise the    lure of an attractant (bait), which may be provided in the    collection chamber. In natural light, the vapour chamber behaves as    a greenhouse raising internal temperatures within the chamber. This    has the effect of pumping out attractant vapour through the process    of gaseous expansion assisted by convection. Convection within the    vapour chamber is also promoted in a preferred embodiment by having    a controlled number of entrance flutes (funnels) which are    positioned at angles to each other. It is particularly preferred to    have four entrance flutes. Increasing the number of flutes tends to    increase the chance of wasp escape and reduces the greenhouse effect    within the chamber. Reducing the number of flutes tends to reduce    the effect of drafts through the chamber dispersing attractant aroma    or vapour.-   1.3 The vapour chamber is preferably designed to capture and retain    wasps. The clear PET plastic encourages the wasps in the chamber to    continue to fly against the wall of the chamber in a bid to escape    rather than being guided to the entrance points. (In other words,    were the chamber to be constructed of opaque or dark or coloured    materials, light entering the chamber through the entrance flutes    would illuminate an escape route for the wasps.)-   1.4 The preferred design of the vapour chamber and the trap may    advantageously prevent or delay the entry of wasps into the    collection chamber, and their immersion in attractant fluid if    present in the collection chamber, preferably for as long as    possible. The reason for this is that the vapour chamber of the trap    provides an environment for wasps from different nests to interact    aggressively, and the restriction between the vapour and collection    chambers prevents the wasps from leaving the vapour chamber too    easily. Wasps from different nests become distressed when in close    proximity and release chemical messengers to both warn and call more    wasps for assistance. This sociological defence mechanism of the    wasps is exploited by the vapour chamber as it promotes prolonged    close proximity of the wasps and prolongs the period during which    the wasps continue to emit the chemical messengers. Once the wasps    are immersed in the attractant or bait (if present in the collection    chamber), which is usually a liquid, then the release of these    distress chemical messengers to the atmosphere is inhibited. The    vapour chamber therefore advantageously has a tall cylindrical    shape, which together with the restriction at the vapour chamber    exit acts to retain wasps in this chamber for as long as possible.    Furthermore, because the vapour chamber is saturated with attractant    vapour, the wasps trapped inside tend to be unable to distinguish    where the attractant vapour is coming from, and so are not led to    the collection chamber by following an increasing vapour    concentration. This is also an important design feature in retaining    the wasps for as long as possible within the vapour chamber.-   1.5 The shape and size of the vapour chamber in the preferred wasp    trap have been determined through a significant amount of    experimentation. It is important to the efficiency of the wasp trap    to have a tall vapour chamber of relatively narrow diameter. The    reason for this is to give wasps trapped in the vapour chamber    sufficient freedom of movement to allow for aerial manoeuvres in    either attacking or escaping from other wasps also captured within    the chamber whilst at the same time confining those movements so    that the wasps within the trap are maintained in close enough    proximity to propagate the distress response. A tall vapour chamber    allows for considerable vertical freedom of flight and this is    consistent with the flight behaviour of wasps for two reasons:    firstly, wasps will drop vertically in a natural defensive manoeuvre    to avoid predators or other wasps, and secondly, wasps then fly    vertically to escape. A tall vapour chamber therefore advantageously    reflects and accommodates this behaviour. Importantly, the tall    design tends to increase the time that a wasp flies in s the vapour    chamber before falling into the collection chamber and any    attractant liquid therein. And also means that the wasps when having    vertically congregate in the same vicinity.-   1.6 The vapour chamber is preferably designed such that the entrance    flutes are sited at a predetermined distance from the top of the    chamber. For example, each entrance is spaced from the top of the    vapour chamber by at least a third of the height of the vapour    chamber. This is important because for the trap to work most    efficiently the wasps should have a “flying zone” within the chamber    in which to compete and interact with other wasps. The inventor has    found that siting the entrance flutes too high up in the chamber    results in more wasps escaping. This is believed to be because wasps    have a tendency to fly vertically, so that they tend to congregate    at the highest part of the chamber.-   1.7 The width of the vapour chamber may also be affected by the    shape of the restriction leading to the collection chamber. For    example, in a preferred restriction is a downward-sloping    frusto-conical funnel, which is preferably sufficiently steep to    prevent wasps from having a perch upon which they can rest.    2. Entrance Flutes-   2.1 The entrance flutes (funnels) are preferably horizontal in    orientation or should have only a shallow slope. The reason for this    is to facilitate ease of access for the wasps. In particular on a    smooth surface, such as a PET surface, wasps are unable to easily    negotiate vertically-orientated or steeply-sloping flutes.-   2.2 The flutes are preferably tapered from a wider entrance to a    narrower exit into the vapour chamber. The reason for this is to    provide an easy landing platform for the wasps, and easy access into    the vapour chamber, whilst the narrower exit means that the wasps    find it more difficult to escape from the vapour chamber.-   2.3 The size of the flutes in the preferred embodiment for trapping    wasps is carefully controlled to allow access for both British and    European varieties of wasp (both foragers and queens) whilst    minimising the size of the escape route.-   2.4 The flutes are preferably of a carefully predetermined length to    reduce the chance of trapped wasps finding the exit. This length has    been determined through experiment and by observing the flight    behaviour of trapped wasps. Wasps flying against the walls of the    trap periodically rebound from the walls but do so without    rebounding by more than a given distance. The flutes are carefully    controlled to this length. Longer flutes prevent rebounding wasps    from escaping but disadvantageously reduce the space for flying    inside the vapour chamber.-   2.5 The flutes are preferably of a number and positioned around the    chamber so as to maximise drafts through the chamber to enhance the    attractant lure of the trap whilst minimising the incidence of wasp    escape and whilst protecting as far as possible the greenhouse    conditions within the vapour chamber.-   2.6. The flutes are preferably staggered in vertical orientation    (vertically spaced) to prevent wasps flying straight through the    trap, and to increase the amount of convection within the trap so as    to enhance the vaporisation of the attractant by continuously    removing more vapour from the trap, so reducing the vapour density    of the attractant in the head space of the trap (i.e. the vappur    chamber), so promoting further evaporation of attractant.    3. Restriction Between Vapour Chamber and Collection Chamber-   3.1 The restriction is preferably designed so as to allow wasps that    are tired to pass or drop through into the collection chamber but to    deter or delay the passage of more energetic wasps into the    collection chamber. Advantageously, the restriction takes the form    of a downward-sloping, frusto-conical funnel at the base of the    vapour chamber, the collection chamber being positioned below the    funnel opening.-   3.2 Wasps have a natural tendency to fly towards light. The    restriction is preferably manufactured in an opaque material, such    as black opaque PET, to guide wasps (which tend to fly towards    light) towards the clear transparent walls of the wasp trap.    Advantageously, both the vapour chamber and the collection chamber    have transparent walls. This effectively helps delay the passage of    wasps into the collection chamber and also helps to retain wasps in    the collection chamber by encouraging them to fly consistently away    from the exit (the restriction) towards the clear walls of the    collection chamber.-   3.3 The restriction is preferably designed to fit sealingly into an    aperture in a safety plug or closure which fits in an opening at the    top of the collection chamber where the collection chamber couples    to the vapour chamber. When the vapour chamber is assembled onto the    collection chamber the restriction preferably prises or urges open a    self-closing mechanism, such as a sprung flap. While the vapour    chamber is disassembled from the collection chamber, the restriction    continues to prevent the escape of wasps from the collection chamber    because a seal between the two is maintained until such time as the    flap or other self-closing mechanism closes. This is a safety    feature of the trap designed to protect the operator from accidental    wasp stings.-   3.4 When the restriction is implemented as a funnel, the slope of    the funnel is preferably more than 50°, and particularly preferably    at least 60°, from the horizontal. This preferably prevents tired    wasps from gaining purchase and prevents them from, resting, and    facilitates the eventual passage of wasps into the killing chamber    once they have become too tired to continue flying in the vapour    chamber. The minimum slope of the funnel may depend on the    smoothness of the material from which it is made. A PET funnel    preferably has a slope of at least 60°.-   3.5 When the restriction is embodied as a funnel, the size of the    funnel opening has been assessed through experimentation and it has    been found that it is preferably linked to the width of the vapour    chamber and slope of the funnel. All of these parameters work    together to provide optimum conditions for the efficacy of the wasp    trap. If the funnel opening is too large, free falling wasps in    defence flight are more prone to fall directly into the attractant    liquid. The funnel helps to prevent this in those wasps that are not    too tired. Furthermore, if the funnel opening is too large, then a    larger and more robust self-closing mechanism may be required. For    example, if a self-closing flap is used then if the funnel opening    is large, the flap may need to be disadvantageously big and, more    importantly, the required depth of the killing chamber may become    impractically large in order to prevent snagging of the self-closing    flap on captured and dead wasps once the chamber starts to fill.    4. Collection Chamber Safety Plug or Closure Apparatus-   4.1 The collection chamber safety plug is a safety feature of    preferred embodiments of the wasp trap, designed to prevent    accidental wasp stings when the collection chamber is being    replaced, for example during re-baiting. If the insects therein are    then to be disposed of safely, it is desirable to be able to seal or    close the container without permitting any insects to escape.

In a first embodiment, the safety plug or closure apparatus mayadvantageously comprise a tubular inlet extending from the vapourchamber funnel opening and a diaphragm, or septum, spanning the openingat the collection chamber entrance. At a central portion of thediaphragm three or more closure elements extend inwardly. The tubularinlet is insertable through the central portion of the diaphragm,resiliently deflecting the closure elements to open the opening into thecollection chamber. Access from the vapour chamber to the collectionchamber is then provided along the interior of the inlet. The inlet isremovable from the diaphragm to allow the resilient closure elements toreturn to their undeflected position to close the opening.

Advantageously, the tubular inlet or inlet passage may be cylindrical orfrusto-conical. In the latter case, the inlet may provide an entrancefunnel. Advantageously, for example, the inlet may provide or comprise apart of the restriction between the vapour chamber and the collectionchamber.

The closure apparatus advantageously comprises four or more closureelements and particularly preferably five closure elements.Advantageously, the closure elements are integral with the diaphragm,which is formed of a resiliently-deformable material, and bounded byslits, or cuts, radiating from a central point. Advantageously, eachslit, or cut, terminates at a stress-relieving hole. This may preventany tendency for the slits to extend or tear under the stress induced bypassing the inlet between the closure elements.

In a preferred embodiment of the closure apparatus, the diaphragm isdomed or otherwise asymmetrically formed (for example conically-formed).In this embodiment, the closure elements in their undeflected positionare not coplanar. This has the effect that a lower force is required toseparate the closure elements from one side of the diaphragm (theconcave side) than from the other (the convex side). This embodiment mayadvantageously help to prevent egress or release of the contents fromthe collection chamber when the closure apparatus is in its closedcondition. This embodiment is particularly advantageous when thecollection chamber may contain live wasps.

A further advantage of this embodiment of the closure apparatus is thatit decreases the angle of deflection of the closure elements when theinlet is inserted through the diaphragm, by comparison with a flatdiaphragm in which the closure elements are coplanar in theirundeflected position. The reduction in opening force and closure elementdeflection both reduce the stresses and strains applied to the closureelements and advantageously ease the demands on the material of theclosure elements.

Advantageously, the diaphragm and the closure elements may be mouldedfrom a resilient material, such as a rubber. Preferably, they may alsobe formed as a single component.

In a further aspect of the closure element, at its periphery thediaphragm may comprise a grommet, or an edge region of enlargedcross-section.

Advantageously, these may be moulded or formed from the same material.The grommet may be shaped for fitting into the entrance of thecollection chamber.

Advantageously, an annular insert may also be provided, which fitswithin the grommet on one side of the diaphragm. The annular insert mayadvantageously retain the grommet within the entrance.

An inner surface of the annular insert may advantageously be shaped soas to receive or guide the inlet of the closure apparatus. Thus, to openthe opening, the inlet may be inserted through the annular insert andthus guided to the central portion of the diaphragm. Further, theannular insert may locate the inlet in position while the opening isopen.

The action of the insert in retaining the grommet within the entranceand guiding the inlet is important because, as the inlet is insertedthrough the diaphragm or is withdrawn, forces are applied to thediaphragm which may tend to dislodge it from the entrance. The insertadvantageously helps to prevent this.

In summary, therefore, in use of this type of trap insects are attractedinto the vapour chamber and eventually fall into the collection chamber.When trapping stinging insects, such as wasps, it is important that thecollection chamber can be sealed without wasps escaping. The closureapparatus is used to couple the vapour chamber to the collectionchamber; the diaphragm spanning an entrance to the collection chamberand the inlet protruding at a lower end of the vapour chamber. To set upthe trap, the vapour chamber is mounted on the collection chamber byforcing the inlet between the closure elements of the diaphragm. Afterinsects have been collected in the collection chamber, the vapourchamber can be removed, withdrawing the inlet of the closure apparatusand allowing the closure elements to close the opening from thecollection chamber. The automatic closure of the collection chamberentrance may advantageously prevent the escape of insects from thecollection chamber.

In a second closure embodiment, the collection chamber safety plug orclosure has a self-closing hinged flap which closes automatically as thevapour chamber is removed. The safety plug of the second embodiment ispreferably manufactured from black opaque PET. Preferably, the depth ofthe safety plug is lower than an upper shoulder of the collectionchamber, in order to retain free flying wasps within the collectionchamber by encouraging them to continue to fly towards the light whichis maximised in the transparent shoulder of the collection chamber.

5. Bait, Collection, or Killing Chamber

In a preferred embodiment, as described below, the collection chambercontains a liquid bait. Vapour from the liquid-passes into the vapourchamber to attract insects such as wasps. When wasps fall from thevapour chamber into the collection chamber they may fall into the liquidbait and be killed, by drowning. Thus, while the collection chamber maybe referred to as a bait chamber or killing chamber, its primaryfunction is to collect insects entering the collection chamber from thevapour chamber. The terms collection chamber, bait chamber and killingchamber may therefore be taken, with reference to various embodiments ofthe invention, to refer to the same general component of the trap.

Bait could mean any attractant or lure and may advantageously, but notexclusively, be located in the collection chamber. Alternatively, baitcould be located in a further chamber, also connected to the vapourchamber, or within the vapour chamber itself.

In the insect trap it may be advantageous to use a liquid bait. Theclosure apparatus may then advantageously provide a sealing effect toprevent bait spillage when the closure elements are in their undeflectedposition.

-   5.1 The collection chamber is preferably manufactured from a clear    plastics material, such as PET. This allows visual inspection of the    amount of wasps which have been captured and killed.-   5.2 The clear design allows examination of the safety closure or    flap (if fitted) to ensure that it is unhindered and capable of    closing during rebaiting.-   5.3 The clear design of the collection chamber advantageously    encourages wasps to continue to fly towards the light and away from    the opening in the restriction.-   5.4 The collection chamber preferably has a line etched onto the    wall of the chamber as a guide beyond which it is not recommended to    capture more wasps. This is a safety feature designed to prevent the    closure apparatus from becoming hindered by the sheer volume of    caught wasps. This may be a problem particularly if the closure    apparatus utilises a self-closing flap.-   5.5 The collection chamber is preferably square or triangular in    horizontal cross section and significantly wider than the vapour    chamber. This is so that once affixed to the vapour chamber, the    collection chamber also acts as a counter weight and stable base.    This may advantageously allow the trap to be used either free    standing or hanging from a support.    6. Collection Chamber Lid-   6.1 To provide a more permanent closure, a lid, such as a screw-on    lid, may be applied to cover the closure apparatus, or the portion    of the closure apparatus (such as a diaphragm or septum) spanning    the collection chamber opening. This may also advantageously provide    a substantially liquid-tight seal.

The lid to the collection chamber may advantageously be designed toscrew onto an upper end of the vapour chamber to provide a fixture forhanging the wasp trap. The lid would then preferably be transparent.

-   6.2 The collection chamber lid is preferably designed to be screwed    onto the vapour chamber for safe-keeping whilst the trap is in use.    The collection chamber may then be re-lidded when it is ready for    replacement and disposal.    7. Mesh Baffle-   7.1 The mesh baffle is an optional feature of the wasp trap which    when fitted to the restriction, will keep trapped wasps or other    insects in the vapour chamber and prevent them from entering the    collection chamber and potentially being killed in the bait (if    present in the collection chamber). This allows the trap to be used    as a humane means of capturing insects during field studies where    there is no intention or need to kill them.

DESCRIPTION OF SPECIFIC EMBODIMENTS AND BEST MODE OF THE INVENTION

Specific embodiments of the invention will now be described by way ofexample, with reference to the drawings in which:

FIG. 1 is a side view of an insect trap according to a first embodimentof the invention;

FIG. 2 is a cross-section of the insect trap of FIG. 1;

FIG. 3 is an isometric view of the bait chamber of the insect trap ofthe first embodiment:

FIG. 4 is a plan view of the bait chamber of FIG. 3;

FIG. 5 is a side view of the bait chamber of FIG. 3;

FIG. 6 is a cross-section of the bait chamber of FIG. 3;

FIG. 7 is an isometric view of the vapour chamber of the trap of FIG. 1;

FIG. 8 is a longitudinal section of the vapour is chamber of FIG. 7;

FIG. 9 is a side view of the vapour chamber of FIG. 7;

FIG. 10 is an isometric view of a coupling ring of the trap of FIG. 1;

FIG. 11 is a plan view of the coupling ring of FIG. 10;

FIG. 12 is a longitudinal section of the coupling ring of FIG. 10;

FIG. 13 is a side view of the coupling ring of FIG. 10;

FIG. 14 is an isometric view of the closure diaphragm of the trap ofFIG. 1;

FIG. 15 is a side view of the diaphragm of FIG. 14;

FIG. 16 is a longitudinal section of the diaphragm of FIG. 14;

FIG. 17 is a view from beneath the diaphragm of FIG. 14;

FIG. 18 is a sectional view of the diaphragm of FIG. 14, on C-C as shownin FIG. 17;

FIG. 19 is a section of a detail B of the diaphragm of FIG. 14, withreference to FIG. 16;

FIG. 20 is a section of a detail D of the diaphragm of FIG. 14, withreference to FIG. 18;

FIG. 21 is an isometric view of the annular insert of the trap of FIG.1;

FIG. 22 is a plan view of the insert of FIG. 21;

FIG. 23 is a longitudinal section of the insert of FIG. 21;

FIG. 24 is a side view of the insert of FIG. 21;

FIG. 25 is an isometric view of the screw-on lid of the trap of FIG. 1;

FIG. 26 is a plan view of the lid of FIG. 25;

FIG. 27 is a longitudinal section of the lid of FIG. 25;

FIG. 28 is a side view of the lid of FIG. 25;

FIG. 29 is a partial section of the lid of FIG. 25 on B-B as shown inFIG. 26;

FIG. 30 is an exploded view of the insect trap of FIG. 1;

FIG. 31 is an isometric view of the insect trap of FIG. 1;

FIG. 32 is an isometric view of the screw-on lid of FIG. 25 attached tothe bait chamber of FIG. 3;

FIG. 33 shows a wasp trap according to a second embodiment of theinvention, assembled for use;

FIG. 34 is a partial plan view of the wasp trap of FIG. 33;

FIG. 35 shows-the wasp trap of FIG. 33 after removal of the baitchamber; and

FIG. 36 is a reproduction of FIG. 35 incorporating dimensions, incentimeters, of a particularly preferred embodiment of the invention.

A first embodiment of the invention will be illustrated with referenceto a trap for wasps, as illustrated in FIG. 1, and shown in section inFIG. 2. The trap comprises a vapour chamber 2 coupled by means of aclosure apparatus 4 to a collection chamber 6. The collection chambercontains liquid bait in this embodiment, and so forms a bait chamber, orkilling chamber, 6. The bait chamber is illustrated in more detail inFIGS. 3 to 6 and the vapour chamber in FIGS. 7 to 9. The bait chamberhas an opening 8 in its upper surface, surrounded by a substantiallycylindrical neck 10. The outer surface of the neck is threaded.

A moulded rubber diaphragm, or septum, 12 fits within the neck asdescribed in more detail below. An annular insert 14 fits within thediaphragm.

The vapour chamber is substantially cylindrical in shape and at itslower end (when oriented for use) terminates in a narrowingfrusto-conical funnel 16 leading to a tubular inlet 18. To assemble thetrap for use, the tubular inlet is inserted through the annular insert14 and then through a central portion of the diaphragm comprising fiveinwardly-extending closure elements 20. When fully inserted, the tubularinlet extends into the bait chamber and the funnel 16 is supported oninner surfaces of the annular insert and the diaphragm. A substantiallycylindrical collar 22 encircles the lower end of the vapour chamber,being retained by engagement with a circumferential lip 24 protrudingfrom the outer wall of the cylindrical portion of the vapour chamber. Alower end of the collar is internally threaded for engagement with theexternally-threaded neck of the bait chamber. Screwing the collar ontothe neck securely retains the vapour chamber in position on the baitchamber. The structure of the collar is shown in more detail in FIGS. 10to 13.

In use of the trap, bait is placed in the bait chamber and the vapourchamber attached to the top of the bait chamber. Vapour from the baitenters the vapour chamber and wasps attracted by the vapour enter thevapour chamber through entrances 26 in its side wall.

The trapped wasps fly within the vapour chamber, emitting distresspheromones which in turn attract further wasps, until they tire and fallinto the funnel at the base of the vapour chamber. The wasps then fallinto the bait chamber from which they are unlikely to escape. This isbecause wasps tend to fly towards light and at least the upper shoulder28 of the bait is chamber is fabricated from a transparent material,attracting the wasps to fly into the corners of the bait chamber andaway from the inlet 18 through which they could return to the vapourchamber.

After the trap has operated for a period of time, the bait chambertypically contains a very large number of wasps and so it is importantto be able to seal the bait chamber reliably for disposal. This isachieved by unscrewing the collar 22 and removing the vapour chamberfrom the bait chamber, whereupon the closure elements 20 resilientlymove together to close the bait chamber entrance. This procedure and thestructure of the closure apparatus at the bait chamber entrance will nowbe described in more detail.

The Closure Apparatus

The closure apparatus comprises the diaphragm 12, which is moulded froma resilient material such as a rubber, and the inlet 18 extending fromthe vapour chamber. The diaphragm is illustrated in more detail in FIGS.14 to 20.

The diaphragm comprises a substantially annular grommet 30 and a domed,or conical, section 32 spanning the interior of the annular grommet.

The neck 10 of the bait chamber primarily comprises a cylindrical wall50, which carries on its outer surface the thread for engagement withthe collar 22. The cylindrical wall is joined to the container portionof the bait chamber at a narrower, waisted portion 52. At its outer end,distant from the container portion of the bait chamber, the neckterminates at a flange 54 which extends inwardly from the cylindricalwall.

The grommet portion of the diaphragm is moulded to be a press fit withinthe neck 10. At its lower edge, the grommet comprises castellations 34which bear on an upper edge of the waisted portion 52 of the neck 10.The castellated structure is used to reduce the volume of rubberrequired to mould the diaphragm. Above the castellations, the grommet isshaped with a substantially cylindrical external wall, to fit againstthe internal wall of the cylindrical portion 50 of the neck. Twocircumferential ribs 38 extend outwardly from the cylindrical wall ofthe grommet and bear against the internal wall of the cylindricalportion to improve sealing. At its upper end, the cylindrical wallterminates at an inwardly-extending circumferential groove 40, whichmatches the inwardly-extending flange 54 of the neck 10. Above thegroove, the grommet terminates at an annular ridge 42, which protrudesabove the neck of the bait chamber when the grommet is in positionwithin the neck.

The domed portion 32 of the diaphragm extends (in use) downwardly fromthe castellations of the grommet and, when the diaphragm is in place inthe neck of the bait chamber, into the bait chamber itself.

The annular insert 14, for insertion within the grommet, is illustratedin more detail in FIGS. 21 to 24. The insert is moulded from asubstantially rigid plastics material. From the upper edge of the inserta flange 72 extends outwardly, being shaped to fit into acircumferential groove 44 defined in the inner-wall of the grommet. Theouter surface of the insert extends downwardly from the flange 72.Adjacent the flange this surface is substantially cylindrical, to matchthe internal surface of the grommet, but at its lower end 74, the inserttapers progressively to match the internal profile of the domed portionof diaphragm. The internal profile of the insert is substantiallyfrusto-conical, tapering inwardly from the flange 72 at its upper edge.The inner surface of the insert is defined by a plurality of fins 76;these reduce the volume of material required to mould the insert. Thefrusto-conical profile is shaped to match the exterior of the funnel 16at the base of the vapour chamber. The frusto-conical interior of theinsert terminates at its narrow end at an opening which is large enoughto guide the tubular inlet 18 at the end of the vapour chamber intocontact with the central portion of the diaphragm beneath, where theclosure elements are located.

In summary, therefore, the diaphragm is fitted into the neck of the baitchamber as follows. As the diaphragm is pressed into the neck, thecastellations 34 engage the waisted portion 52 at the base of the neck10 to prevent the diaphragm from falling into the bait chamber. When thediaphragm is seated in the neck, the flange 54 extending inwardly at theupper edge of the neck seats in the external groove 40 of the diaphragm.The insert is then press fitted within the diaphragm, until the externalflange 72 at the upper edge of the insert enters the internal groove 44within the diaphragm. The upper edge of the grommet is chamfered toguide the insert into this position. When the insert is in position, itacts to prevent the rubber grommet from deforming and coming free fromthe flange 54 surrounding the neck of the bait chamber. In addition, theinsert is sized such that, when press fitted within the grommet, iturges the grommet against the internal surface of the neck. This helpsto ensure a liquid-tight seal, particular between the ribs 38 and thecylindrical surface of the neck.

The Closure Elements

At the central portion of the diaphragm, five substantially triangularclosure elements 80 extend inwards, as shown in FIG. 17. These aredivided by slits 82 extending outwardly from a common point at thecentre of the diaphragm. Each slit terminates at a circular,stress-relieving hole 84. The closure elements are moulded from the sameresilient material as the remainder of the diaphragm and, when the inlet18 is inserted through the central portion of the diaphragm, resilientlydeflect outwards, as shown in FIG. 2. As the closure elements deflect,the stress-relieving holes 84 prevent tearing of the diaphragm.

When the diaphragm is initially moulded, the slits 82 are defined bychamfered grooves 86 but these do not penetrate entirely through thediaphragm and so the slits themselves are not formed. The slits areformed by tearing of the rubber at the base of each groove 86 as theinlet is first inserted through the diaphragm. Details of thisconstruction are shown in FIG. 20. This enables the diaphragm to providea completely liquid-tight seal before the first assembly of the trap.For this purpose, the stress-relieving holes 84 may not comprise holesthrough the entire thickness of the diaphragm, but regions in which thethickness of the diaphragm is substantially reduced. These aspects ofthe diaphragm construction enable bait to be provided, sealed within thebait chamber, and vapour only released when the trap is assembled andready for use.

The domed or conical shape of the portion of the diaphragm comprisingthe closure elements provides a number of advantages. First, it reducesthe angle through which the closure elements are deflected as the inletis forced between them. This advantageously reduces the loading on therubber material of the closure elements. Further, the reduced deflectionof the closure elements helps the closure elements to lie close to or incontact with the external surface of the tubular inlet when inserted.This advantageously reduces the possibility that wasps may find theirway out of the bait chamber between the closure elements and the inlet.

As the vapour chamber and the bait chamber are assembled and the inletis inserted through the diaphragm, a force is applied to the diaphragmtending to push it into the bait chamber. Contact between thecastellations of the grommets and the waisted portion of the neckprevent this. In this area of the diaphragm, the insert also preventsthe grommet from distorting and falling into the bait chamber.

When the vapour chamber is removed from the bait chamber, the baitchamber may be filled with wasps. As the inlet is withdrawn from theclosure elements, a force is applied to the diaphragm tending to pull itout of the neck of the bait chamber, which is undesirable as it wouldrelease the wasps. This is prevented by the interaction of the grommetwith the flange 54 at the upper end of the neck. This is assisted by theaction of the insert. As the inlet is withdrawn, the closure elementsare pulled upwards towards and against the rigid insert. This force istransferred through the insert to the grommet and thus to the flange atthe upper end of the neck of the bait chamber preventing removal ordistortion of the grommet portion of the diaphragm.

As the inlet is withdrawn, there may be a tendency for one or more ofthe closure elements to adhere to the inlet. The profile of the loweredge of the insert is rounded, and the inner opening of the insert issufficiently large, to prevent any closure elements adhering to theinlet from jamming within the insert (between the inlet and the insert)as the inlet is withdrawn. The opening in the insert is, however,sufficiently small to prevent any wasps escaping as the inlet iswithdrawn as a result of being caught between a closure element and theinlet.

When the vapour chamber has been removed from the bait chamber, theclosure elements resiliently recover into contact with each other,closing the bait chamber and preventing the escape of any trapped wasps.A further advantage of the domed, or conical, shape of the centralportion of the diaphragm is that a greater force is required to pressthe closure elements open from within the bait chamber than from outsidethe bait chamber. Thus, even if the bait chamber is accidentallyinverted after the diaphragm is closed, no insects should escape.

Finally, a screw-on lid 90 is provided for the bait chamber. This isshown in FIGS. 25 to 29. After the vapour chamber has been removed, thelid is simply screwed onto the bait chamber to provide a permanent seal.The annular ridge 42 at the upper edge of the grommet extends beyond theflange 54 at the upper edge of the neck in order to provide a rubberseal against which the lid can close, to provide a liquid-tight seal.

When the vapour chamber is coupled to the bait chamber, the lid 90 canconveniently be stored at an upper end of the vapour chamber as shown inFIGS. 1, 2 and 31. A hook or eye 92 is moulded on an upper surface ofthe lid, from which the trap can be suspended if desired when the lid isin this position.

FIGS. 33 to 36 illustrate a wasp trap according to a second embodiment,comprising a vapour chamber 102 coupled at a screw thread 104 to anopening in the top of a collection chamber 106. As in the firstembodiment, the collection chamber is suited to contain liquid bait andso may be termed a bait or killing chamber. The vapour chamber ispositioned vertically above the bait chamber and the assembled trap canstand on the flat base 108 of the bait chamber. The bait chamber can beunscrewed to remove it from the vapour chamber and can then be sealedusing a threaded lid 110. When the bait chamber is coupled to the vapourchamber the lid can be screwed onto a thread at the upper end of thevapour chamber for safe keeping. The lid is also provided with aprotruding tab, or eye, 112 to which a string can be attached, so thatthe trap may be suspended during use, for example from the branch of atree.

The vapour chamber 102, the bait chamber 106 and the lid 110 are alladvantageously moulded from a transparent plastics material, such asPET.

The vapour chamber is circular in cross section as shown in FIG. 34, andfour insect entrances 114 are formed in its vertical side wall. Eachentrance is surrounded by a frusto-conical flange 116 which extends intothe vapour chamber, ending at a narrow opening 118. The entrances aresubstantially horizontally oriented so that wasps can easily crawl orfly into the vapour chamber. The length of each flange is predeterminedso that wasps flying within the vapour chamber and rebounding from itswalls do not rebound beyond the flanges.

In use, a bait is placed in the bait chamber to release an aroma, whichpasses into the vapour chamber and out of the insect entrances, to lureinsects into the trap.

The bait is typically liquid and wasps entering the bait chamber arelikely to drown in this liquid.

None of the insect entrances are aligned with each other and all fourentrances are at different heights. The inventor has found that avoidingalignment of the entrances reduces the number of wasps which escape fromthe vapour chamber and that vertically spacing the entrances enhancesthe release of bait aroma from the vapour chamber. In addition, theentrances are circumferentially spaced around the vapour chamber, sothat wind from any direction passes through the vapour chamber todistribute bait aroma.

At the lower end of the vapour chamber a restriction 120 comprises afrusto-conical flange, or funnel, 122 extending downwardly from the wallof the vapour chamber to a narrower circular opening 124, from which acylindrical tube 126 extends into the bait chamber. The restriction isopaque, either being coloured or moulded from an opaque plasticsmaterial.

Wasps tend to fly towards light, and in the vapour chamber willtherefore tend to fly away from the restriction towards upper portionsof the vapour chamber. When a wasp is tired, however, it is desirablethat it should enter the bait chamber without delay, and so the angle ofthe sloping portion of the restriction is chosen to be too steep toallow wasps to rest on it.

The bait chamber has a circular opening surrounded by a cylindrical wall128, which is externally threaded to engage either the lower end of thevapour chamber or the bait chamber lid. A safety plug 130 is a push fitwithin the cylindrical wall and includes a flange 132 which extendsradially inwards to a central opening, which fits snugly around an outersurface of the cylindrical tube 126 of the restriction when the baitchamber is threaded onto the vapour chamber. The safety plug alsocomprises a self-closing flap 134 which is biassed by a spring 136towards a closed position, in which it seals the central opening of thesafety plug. As the bait chamber is threaded onto the vapour chamber, anend of the cylindrical tube 126 urges the flap 134 into an open positionas shown in FIG. 33. As the bait chamber is unscrewed from the vapourchamber, the cylindrical tube is withdrawn, allowing the flap to sealthe opening in the safety plug before the bait chamber is fullyunscrewed.

FIG. 35 shows the bait chamber removed from the vapour chamber, with theflap closing the opening in the safety plug and the bait chamber lid inplace.

The safety plug is moulded from an opaque material. Since wasps withinthe trap tend to fly towards light, this reduces the tendency for waspsto fly out of the bait chamber back into the vapour chamber. It shouldbe noted that transparent shoulders 138 of the bait chamber extendoutside and above the bottom of the safety plug. Wasps flying in thebait chamber tend to fly into these shoulders and away from the openinginto the vapour chamber.

In an alternative embodiment, the trap may be used for collectinginsects alive. In this case, as illustrated in FIG. 35, a cylindricalinsert 140 carrying a mesh baffle 142 can be pressed into thecylindrical extension 126 of the restriction. The insert is shaped sothat the cylindrical tube can still open the flap in the safety plug.However, the baffle covers the opening between the vapour chamber andthe bait chamber so that bait aroma can still be released by the trapbut wasps in the vapour chamber cannot enter the bait chamber. Wasps canthen be caught alive in the vapour chamber.

FIG. 36 is a reproduction of FIG. 35 and shows the dimensions of anembodiment of the trap, in centimeters. It also shows the preferredangle for the sloping portion of the restriction 120. Although thesedimensions have been found by the inventor to produce a highly effectivewasp trap, the skilled person would readily appreciate that the designfactors described in this patent application would provide guidance toallow effective traps of different dimensions to be designed, and thatsuch traps therefore fall within the scope of the present invention.

Further Aspects

It has been noted that trapped insects, such as wasps, may tend to flytowards light. After trapping such insects it may be desirable to ensurethat all have entered the collection chamber, and that the vapourchamber is empty, before removing the collection chamber from the vapourchamber. To do this it may be advantageous to cover the vapour chamber,but not the collection chamber, with an opaque or substantially opaquecloth or sleeve for a predetermined time. This closes the insectentrances into the vapour chamber to prevent entry of further insectsand encourages those in the vapour chamber to enter the collectionchamber, which is still lit through its transparent walls. The inventorhas found that covering the vapour chamber in this way for about oneminute is sufficient to clear the vapour chamber.

It has also been noted above that trapped insects can be sealed in thecollection chamber for disposal. The vapour chamber is then availablefor reuse. In a preferred embodiment, therefore, new collection chamberscontaining bait can be advantageously supplied for fitting to thereusable vapour chamber. It may be undesirable to reuse collectionchambers as it is safer, particularly when trapping stinging. insects,to dispose of the trapped insects sealed within the collection chamber.

A further advantage found by the inventor is that traps embodying theinvention may selectively trap certain types of insect. A particularlybeneficial example is that a trap set up in an apiary may selectivelytrap wasps and not bees. It is believed that this may be due to theemission of stress pheromones by trapped wasps attracting only furtherwasps and not bees.

1. A wasp trap, comprising; a vapour chamber detachably couplable to acollection chamber; the vapour chamber having a property to form a vaporthat is based on an attractant material within the wasp trap, the vapourchamber including: a wasp entrance defined in a wall of the vapourchamber; a restriction part connected to the vapour chamber, therestriction part being sized to control the movement of wasps from thevapour chamber to the collection chamber when coupled, and therestriction part includes a surface sloping downwardly towards anopening into the collection chamber; a tubular inlet extendingdownwardly from the restriction part; and the collection chamberincluding: a housing, an entrance into the housing, and a self-closingpart designed to automatically seal the entrance when the collectionchamber is detached from the vapour chamber in order to prevent escapeof wasps from the collection chamber; the self-closing part includes aresilient diaphragm with three or more inwardly-extending resilientclosure elements, and the diaphragm is dome shaped toward an interior ofthe housing so that the closure elements are more easily deflected toopen the diaphragm in an opening direction toward the interior of thehousing; wherein during coupling of the vapour chamber and thecollection chamber, the tubular inlet is insertable through thediaphragm which will deflect the resilient closure elements in theopening direction to open the entrance, and is thereafter removable toallow the resilient closure elements to return to their undeflectedposition to close the entrance; the wall of the vapour chamber issubstantially transparent, at least a portion of the collection chamberis transparent, and the restriction part is opaque.
 2. The wasp trap ofclaim 1, wherein the vapour chamber includes a collar rotatably mountedthereon for rotation relative to the wall, the collar including athread; and the collection chamber includes a thread that is engageablewith the thread on the collar whereby the vapour chamber and thecollection chamber are detachably couplable.
 3. The wasp trap of claim1, comprising a plurality of wasp entrances defined in the wall, theentrances being vertically spaced from each other on different verticallevels and circumferentially spaced from each other, none of the waspentrances are aligned with each other, and a vertically uppermost saidwasp entrance is spaced from a top end of the vapour chamber by at leasta third of the height of the vapour chamber.
 4. The wasp trap of claim1, wherein the collection chamber has a width in a plan view that isgreater than a width of the vapour chamber.
 5. A wasp trap, comprising:a vapour chamber defined by a wall, the chamber having a top end and abottom end defining a height therebetween, and the wall is substantiallytransparent; a plurality of wasp entrances defined in the wall, theentrances being vertically spaced from each other on different verticallevels and circumferentially spaced from each other, none of the waspentrances are aligned with each other, and a vertically uppermost saidwasp entrance is spaced from the top end of the vapour chamber by atleast a third of the height of the vapour chamber; a collection chamberdetachably couplable to the vapour chamber at a restriction that issized to delay the passage of wasps from the vapour chamber to thecollection chamber, the restriction includes a surface slopingdownwardly towards an opening into the collection chamber; at least aportion of the collection chamber is transparent, and the restrictionpart is opaque; and a self-closing mechanism for automatically sealingthe collection chamber as it is detached from the vapour chamber, inorder to prevent trapped wasps escaping from the collection chamber. 6.The wasp trap of claim 5, wherein there is a single said entrance oneach vertical level.
 7. The wasp trap of claim 5, wherein the vapourchamber includes a collar rotatably mounted thereon for rotationrelative to the wall, the collar including a thread; and the collectionchamber includes a thread that is engageable with the thread on thecollar whereby the vapour chamber and the collection chamber aredetachably couplable.
 8. The wasp trap of claim 5, wherein thecollection chamber has a width in a plan view that is greater than awidth of the vapour chamber.
 9. A wasp trap system, comprising: a vapourchamber having a transparent wall; the chamber having a top end and abottom end; a plurality of wasp entrances defined in the wall, theentrances being vertically spaced from each other on different verticallevels and circumferentially spaced from each other, and none of thewasp entrances are aligned with each other; a conical restriction partintegrally connected to the wall adjacent the bottom end of the vapourchamber; and a tubular inlet extending downwardly from the conicalrestriction part; and a collection chamber detachably couplable to thevapour chamber, the collection chamber includes a housing, a singleentrance into the housing, and a self-closing part designed toautomatically seal the entrance.
 10. The wasp trap of claim 9, whereinthere is a single said entrance on each vertical level.
 11. The wasptrap of claim 9, wherein the vapour chamber includes a collar rotatablymounted thereon for rotation relative to the wall, the collar surroundsat least a portion of the conical restriction part, and the collarincludes a thread; and the collection chamber includes a thread that isengageable with the thread on the collar whereby the vapour chamber andthe collection chamber are detachably couplable.
 12. The wasp trap ofclaim 9, wherein at least a portion of the collection chamber istransparent, and the conical restriction part is opaque.
 13. The wasptrap of claim 9, wherein the collection chamber has a width in a planview that is greater than a width of the vapour chamber.
 14. A wasptrap, comprising; a vapour chamber configured to form a vapour fromattractant material placed within the trap; a wasp entrance defined in awall of the vapour chamber; a collection chamber detachably couplable tothe vapour chamber at a restriction that is configured to delay thepassage of wasps from the vapour chamber into the collection chamber,the restriction includes a surface sloping downwardly towards an openinginto the collection chamber; the wall of the vapour chamber issubstantially transparent, at least a portion of the collection chamberis transparent, and the restriction is opaque; and a self-closingmechanism connected to the collection chamber for automatically sealingthe collection chamber as it is detached from the vapour chamber inorder to prevent trapped wasps escaping from the collection chamber. 15.The wasp trap of claim 14, wherein the vapour chamber includes a collarrotatably mounted thereon for rotation relative to the wall, the collarincluding a thread; and the collection chamber includes a thread that isengageable with the thread on the collar whereby the vapour chamber andthe collection chamber are detachably couplable.
 16. The wasp trap ofclaim 14, comprising a plurality of wasp entrances defined in the wall,the entrances being vertically spaced from each other on differentvertical levels and circumferentially spaced from each other, none ofthe wasp entrances are aligned with each other, and a verticallyuppermost said wasp entrance is spaced from a top end of the vapourchamber by at least a third of the height of the vapour chamber.
 17. Thewasp trap of claim 14, wherein the collection chamber has a width in aplan view that is greater than a width of the vapour chamber.